1. Field of the Invention
The invention relates to a method for adjusting brightness of a light source, and more particularly to a method for adjusting brightness of a light source by turning on and off the light source.
2. Description of the Related Art
When conventional illumination devices, such as white lamps, fluorescent lamps, and light emitting diodes, are lit, they provide light sources with fixed brightness. In some conditions where high brightness is not required, energy is wasted by the superfluous brightness provided by the illumination devices. Additionally, it is often inconvenient for users to change brightness of the illumination devices to provide appropriate brightness according to surrounding environment conditions. Thus, appropriate brightness is an important issue for illumination devices.